It is well known that many naturally occurring microorganisms are capable of biodegradating hydrocarbon contaminants found in soils and water. Unfortunately, these naturally occurring microorganisms are not capable of biodegrading the hydrocarbon contaminants at sufficiently rapid rates to be able to render biodegradation as a practical process for depolluting hydrocarbon contaminants from soils and water. One factor believed to be contributing to the relatively slow rate of biodegradation of hydrocarbon contaminants in soils and water by the naturally occurring microflora is lack of adequate microbial nutrients. Therefore, it has been proposed to stimulate the proliferation and activity of hydrocarbon degrading microorganisms by adding nutrients such as nitrogen and phosphorous to the sites requiring bioremediation. Indeed, perhaps the first large scale demonstration of the beneficial effects of microbial stimulation as a means of enhancing natural bioremediation occurred at Prince William Sound in Alaska, following the 1989 oil spill, where a slow release solid fertilizer was applied over many miles of beach to supplement the naturally available nitrogen and phosphorous. Notwithstanding the success of that demonstration, there still remains a need for improving the bioremediation of contaminated soils and water.
Accordingly, it is an object of the present invention to enhance microbial growth and activity by providing contaminated soils and water with nutrients released at a rate which is more consistent with the growth needs of the microflora.
It is another object of the present invention to improve microbial biodegradation of contaminated soils and water by providing the release of microbial nutrients at a rate which more effectively matches the microbial needs under differing temperature conditions.
These and other objects of the present invention will become more apparent upon a reading of the description of the invention which follows: